Galaxy
Galactic tensions are rising due to batarian Ambassador Jath'Amon's arranging of a meeting with the Citadel Council, with the intention of negotiating peace terms between the batarians and the Alliance. Jacob Taylor is on vacation aboard the passenger liner Arcturian Jade when the ship is attacked by batarian terrorists. Jacob grabs his assault rifle, kept from his former job as an alliance marine, and battles the batarians while defending the crew and passengers. After taking out the batarian attackers, Jacob is thanked by the Captain, Reginald Tudge, who gives Jacob the choice of any quarters on the ship in gratitude. Jacob arrives at the Citadel and is greeted by his former CO, Major Derek Izunami, who is seeking Jacob out for a mission in the Nemean Abyss, as Jacob is no longer restricted by Alliance military boundaries. He asks Jacob to meet Miranda Lawson, an informant who may have information on the batarian's recent crime wave, in a bar called the Fringe on Cartagena Station. When Jacob arrives, the Fringe has been taken over by a band of pirates led by Clint "Black Eye" Darragh. Jacob can either convince him to retire or take him on in combat. Once he is taken away, Jacob is greeted by Miranda, who was watching the confrontation from the bar. Miranda explains the batarian extremists' plan to attack the Citadel on the day of Jath'Amon's arrival and sabotage the peace talks by killing him. She gives him three sources on where to start the investigation: A turian arms dealer named Illo Nazario on the planet Tortuga who has worked with the batarians for years, the planet Bekke where a batarian army is reportedly gathering, and a rumor that the batarians have kidnapped several scientists and are holding them on the Ahn'Kedar Orbital Platform. On Tortuga, Jacob is met by a salarian friend of Miranda's, Ish, who has the access codes for Nazario's compound. Apparently, Nazario hasn't made any deals for weeks, which has drawn suspicion. As Jacob makes his way through the compound full of turian guards, a unit of batarians will attack. Their leader claims they came to talk to Nazario. Jacob can convince them to turn back or fight them. Jacob reaches Nazario, who is deathly ill. Nazario reveals that the batarians have tested a weaponized virus on him and bargains with Jacob for a vaccine: Jacob will have Nazario's information about the virus, as soon as Jacob gets him the cure. When Jacob arrives at the Ahn'Kedar Orbital Platform he immediately suspects the research carried out there is just a front. A batarian businessman challenges him, but before he can act, a krogan named Nax appears and begins gunning down the batarians. Nax gives Jacob till the count of five to "justify his life". When he either reaches two or is convinced by Jacob, they realize they have a similar goal; Jacob is there to rescue the scientists, among whom is Batha, an asari and old friend of Nax who he infiltrated the facility in order to rescue. After defeating several waves of batarians, including their leader, Jacob discovers the scientist Dr. Hendricks, who seems more upset about Jacob interrupting their work than having been taken hostage. Hendricks claims the batarians have fallen prey to a terrible disease, which has wiped out entire populations. The disease, a blood plague, is communicable only in high concentrations, incubates very quickly, and has a 100% fatality rate. He claims the batarians brought the scientists there to develop a cure. Once Jacob convinces Hendricks to leave, he discovers the prototype formula for the cure is held by Batha, who is in another facility. At that moment Nax bursts through the door with Batha in his arms, under heavy fire from the batarians. Jacob saves him and brings him on board his ship. Once on board, Batha reveals the batarian claim of a virus was fake. The batarians only wanted to convince the scientists to make a cure for their blood plague weapon. The crew realizes they need to get the cure to the Citadel in anticipation of the attack. Though the cure is only a prototype, Batha nearly finishes it using supplies from the ship's med labs, but she requires a final ingredient—a large quantity of unrefined element zero. When Jacob's crew arrives on the rainy mining colony of Bekke, the ship immediately comes under gunfire as Miranda picks up strange readings from the planet. Jacob fights his way into the facility, but begins feeling sick and dizzy due to the batarians' stash, a huge cache of improperly stored element zero. The closer Jacob gets to the eezo, the more strain it puts him under due to his biotic abilities, though it has the beneficial effect of strengthening his powers. Once Jacob defeats the resident batarians, Miranda urges him to leave the facility at once so she can pick up the shipment of element zero. Batha then uses the haul to complete the cure. Returning to Nazario, Jacob can finally interrogate him. Jacob discovers from him that the batarians' true target is the Citadel Council, and not Ambassador Jath'Amon as previously thought. Knowing Jacob holds his only hope of survival, Nazario also reveals that the leader of the batarian extremists is in fact Jath'Amon himself, who intends to infect the Council with the bioweapon during his peace talk. Jacob and Miranda hurry back to the Citadel to stop the meeting. Jacob heads to the Citadel Tower, but all seems quiet. Jacob is stopped by a C-Sec officer, who is exposed as a batarian, revealing they have infiltrated Citadel Security itself. Battling his way up to the tower, Jacob enters the council chambers in the middle of the ambassador's speech and the asari council representative questions Jacob's intrusion. Jacob brings the evidence against Jath'Amon to light, and Jath'Amon's peaceful demeanor fades as Jacob lays out his plan. The asari council representative apologizes, but says she won't risk the Council until she is sure of Jacob's claims. The furious ambassador reveals that the virus was concealed within his hover chair, and releases it into the citadel tower before flying away. Jacob warns everyone to escape, then takes on the ambassador's batarian troops and combat drones. After Jacob finally defeats Jath'Amon, he tells Jacob that they are not so different; as both of them are willing to go to great ends to protect their people. Jath'Amon swears revenge on Jacob and the Council as he is led away by Citadel Security. After resuming his vacation on the Arcturian Jade, Jacob is watching a news report about Jath'Amon's arrest when he is surprised by a noise behind him. After grabbing his assault rifle, he realizes the intruder is Miranda, with a bottle of champagne and a smile.